Counter-rotating earth drill



May 4, 1965 1. P. NIELSEN COUNTER-ROTATING EARTH DRILL F'iled Aug. 24, 1962 3 Sheets-Sheet 1 ATTORNEY y 1965 I. P. NIELSEN 3,181,631

COUNTER-ROTATING EARTH DRILL Filed Aug. 24; 1962 3 Sheets-Sheet 2 I INVENTOR- IRV/ F. N/ LSEN MW ATTORNEY United States Patent 3,181,631 COUNTER-ROTATING EARTH DRILL Irvin P. Nielsen, Glenwood Springs, Colo., assiguor of one-half to Cameron and Jones, Incorporated, Denver, (1010., a corporation of Colorado Filed Aug. 24, 1962, Ser. No. 219,268 Claims. (Cl. 175-96) This invention relates to the production of earth bores, and more particularly to the production of deep such bores appropriate for the testing, evaluation, and tapping of sub-surface strata having petroleum-bearing potential, and has as an object to provide novel and improved means operable to generate such bores with enhanced efliciency and practicality.

A further object of the invention is to provide a novel and improved earth drill that is directly self-powered for penetrating effects.

A further object of the invention is to provide a novel and improved earth drill that is operable with intended effect in suspension from a flexible line independently of other mechanical association with surface-based actuating equipment.

A further object of the invention is to provide a novel and improved earth drill that is operable with intended effect in suspension from a flexible line without recourse to directional restraints other than those inherent in the drill organization.

A further object of the invention is to provide a novel and improved earth drill that is particularly adapted for the effective generation of small-diameter, deep bores con sequently susceptible of completion without resort to casing during the drilling operation.

A further object of the invention is to provide a novel and improved earth drill characterized by separate, concentric bit components powered for opposite rotation.

A further object of the invention is to provide a novel and improved earth drill characterized by separate, concentric bit components individually powered for rotation in opposite directions.

A further object of the invention is to provide a novel and improved earth drill characterized by separate, concentric bit components individually and directly powered for rotation in opposite directions as exposed terminals of a unitary, internally-powered organization.

A further object of the invention is to provide a novel and improved earth drill distinguished by separate, concentric bit components independently powered in a unitary organization for rotation in opposite directions and automatic torque balance.

A further object of the invention is to provide a novel and improved earth drill organized and internally powered as a unitary assembly operable in suspension from a flexible line to actuate separate, concentric, individually-driven bit components in opposite directions and in a torque balance inhibitive of rotational assembly reaction.

A further object of the invention is to provide a novel and improved construction and operative correlation of elements constituting an earth drill appropriate for the generation of deep, small-diameter bores with efficiency and economy.

A further object of the invention is to provide a novel and improved construction and operative correlation of elements constituting a unitary assembly of separate, concentric bit components and means directly and independently powering the separate components for rotation in opposite directions.

A further object of the invention is to provide a novel and improved construction and operative correlation of elements constituting a unitary assembly of separate, concentric bit components and means directly and independently powering the separate components for synchronous rotation thereof in opposite directions and maintained torque balance.

A further object of the invention is to provide a novel and improved earth drill of dual-bit, internally-powered, counter-rotating type that is compact in a unitary organization expediently practical of use, that is feasible of production and operation with etficiency and economy, that accommodates conventional use of cooling and scavenging fluids, that obviates occasion for massive and expensive surface works as prerequistes to bore generation, that is operable with but moderate power demand, that is inherently self-guiding in the production of straight bores, and that is amenable to rapid and convenient rehabilitation and replacement of its bit components.

With the foregoing and other objects in view, my invention consists in the construction, arrangement, and operative combination of elements as hereinafter set forth, pointed out in my claims, and illustrated by the accompanying drawings, in which FIGURE 1 is a side elevational view of a typical embodiment of an earth drill exemplifying the principles of the instant invention as organized ready for practical use, intermediate length portions of the assembly being broken away to conserve space.

FIGURE 2 is a longitudinal section, on a relativelyenlarged scale, taken substantially axially of the organization according to FIGURE 1 with intermediate length portions broken away to conserve space.

FIGURE 3 is a transverse section, on a further enlarged scale, taken substantially on the indicated line 33 of FIGURE 2.

FIGURE 4 is a transverse section, on the same scale as FIGURE 3, taken substantially on the indicated line 44 of FIGURE 2.

FIGURE 5 is a transverse section, on the same scale as FIGURES 3 and 4, taken substantially on the indicated line 5-5 of FIGURE 2.

FIGURE 6 is a transverse section, on the same scale as FIGURES 3, 4 and 5, taken substantially on the indicated line 6-6 of FIGURE 2.

FIGURE 7 is a transverse section, on the same scale as FIGURES 3, 4, 5 and 6, taken substantially on the indicated line 7-7 of FIGURE 2.

FIGURE 8 is a diagram of an exemplary arrangement of electrical connection, components, and instrumentalities elfective to power the earth drill represented by the preceding views for intended operation distinctively characteristic of the invention.

FIGURE 9 is a fragmentary, detail section showing the lower end of the organization according to FIGURE 2 as modified within the contemplation of the invention to function as a core drill.

In any expedient particular construction and desired size, the features, components, and facilities correlated to operatively comprise the earth drill of the invention are carried by or associated with an elongated tubular housing 10 having a maximum exterior diameter slightly less than that of the bore resulting from operation of the drill. To facilitate production, servicing, and rehabilitaion of the earth drill, the housing It) is preferably constructed as a lower, right-cylindrical barrel portion 10 of the desired maximum exterior diameter and an upper, right-cylindrical barrel portion 10" having an exterior diameter reduced relative to that of the portion 10' separably coupled, as by means 11, in fixed, coaxial relation.

Suitably closed and sealed, as by means of a plug 12, a cap 13, and a clamp nut 14, the upper end of the barrel portion 10" is fixed in engagement with a bail 15 adapted in extension axially and outwardly therefrom for connection to the lower end of a line 16, such as a flexible cable,

housing may be suspended with its axis vertical in altitudinally-reciprocable dependence from surface-based Works of appropriate conventional arrangement.

' Revoluble'coaxially'of. the lower'barrel portion 10', as in suitable anti-friction bearings 17., a tubular sleeve 18 traverses said barrel portion to project outwardly and downwardly thence through and for unrestricted rotation relative to. a suitable arrangement of means, such asa cap 19 and seal 20, closing the lower end thereof. The sleeve 18 functions as the rotor shaft of a squirrel-cage electric motor, whereof the rotor element 21 are fixed exteriorly to, circumferentially about, and in longitudinal alignment on the sleeve in appropriately-spaced opposition to motor stator elements 22 correlatively fixed to the interior of the barrel portion;10 whereby to complete a power uniteffective in reaction to supply of suitable energy to the sta tor elements 22 to rotate .the sleeve l8 relative tothe barrel portion wherein it is journaled. A Revolubly supported, as by anti-friction bearings 23, coaxially and through the major length of the upper barrel portion 10",a' tubular stem 24, traverses and is rotatably accommodated within theisleeve 18 to project. slightly therebeyond exteriorly of the housing 10, which stem 24, in analogy with thesaid sleeve 18, functions as the rotor shaft of a' second squirrel-cage electric motor whereof the rotor elements 25 are operatively opposed in fixed association with thestemto stator elements 26 correlatively fixed to the interior of the barrel portion10", whereby to establish within the housing 10 a second and independent power unit effective to rotate the said stem 24 relative to the barrel portion thereby traversed when suitable energy is supplied to the stator elements 26. Indicative of any feasible arrangement for the circulation of cooling and scavenging fluids through the organization typified by the housing 10, the stem 24 is represented as open throughout its length and as'communieating at its, upper end through an appropriate packing gland 27, or .the equivalent, with a chamber 28in the upper end of the barrel'portion 10 to which fluids may be delivered from a conventional surface-based pressure related with the manipulating line 16 and opening to said chamber through the plug 12, or otherwise. In addition,

circulation of cooling'and scavenging'fluidsimay be had, when desired, through passages 30-in' the wallsof the barrel portions 10' and10 communicating between .the chamber 28 and outlets at or adjacent the lower end of the housing 10. in'any desired feasible arrangement. When deemed to be appropriate, the squirrel-cage motors utilized to drive the sleeve 18and stem 24 may be of v.eneapsulated type accommodating circulation of cooling and scavenging fluids directly ther'ethrough in any expedient manner land coaction of means alternative to that shown and described, all of which is clearly within the scope and contemplation of the invention.

Conditioning the assembly typified by the housing 10- for intended use as an earth drill, the end of the stem 18 projecting axially from the lower end of the. barrel portion 10' operatively and detachably mounts for rotation therewith an annular bit component 31 having a major diameter slightly exceeding that of the barrel portion 10 i and a diameter of central opening approximating or exceeding the exteriordiameter of the associated sleeve. The bit component 31 may be of any specific construction and configuration suited to attainment of its func- .ment thereof. To complement the excavating action of the bit component 31,'a bit component 32 detachabl secured to the projecting lower end of the stem 24 is adapted for rotation with the latter independently of and out of contact with the said component '31; said component 32 being of any construction and configuration suited to attainment of its function of supplementing the excavating efifect of thecornponent 31 and being represented in FIG- URES 1 and ,2 as. an abrasively-armored, bulbous body having an exterior diameter slightlyexceeding and spaced: ly overlapping the diameter-of the central opening in the component 31, a convexly-lobed terminal face opposed to the material to be excavated within the channel orbit of the component 31, and radially-disposed, fluid-directing grooves across said terminal face from communication with the fiuid supply interiorly of the stem 24, whileFIG- URE 9 represents the component 32 as of an annular form suited in coaction with thecomponent 31 to gen erate a core centrally of the material under excavation for reception within and recovery from the interior of the stem 24 modified to serve as a core barrel,"as is'known and conventional practice. l --:Squirrel-cage motors of the type utilized to. rotatably power the sleeve .18 and s'tem 24loperate in reaction to three-phase supply of alternating current acting upon and through'the stator, elements of the motors, and current supply effective for such purpose is applied independently and directly to the stator elements 22 and 26 of the separate motors of the assembly typified by the housing 10 through the agency of three-wire cables 33, one for each of the said motors, which flexibly'parallel the manipulating line 16 as extensions in parallel from a common supply circuit to operatively connectthroughand along thewalls ofthe housing with the stator elements of the respective motors, In any expedient arrangement, represented as triple leads 34 of one of thecables 33 connecting with and to serve the stator elements 22 of the lower motor and triple leads'35 of the other of said cables connecting with and to serve the stator elements 26 of the upper motor, current from the supply circuit is made simultaneously. and reversely available to the separate upper and lower motors of the earth drill assembly in an established and well-known manner efiective when the rotational drive ,of'the sleeve 18 carrying the. bit component 31 and the stem 24 carrying the bit component 32 in correspondingly opposite directions, whereby efliciently to apply a'ndto advance the excavating potential of the complementary bit components.

' A significant and distinguishing factor featuring the invention is maintenance of balance between the torques incident to'separate drive of the counter-rotating bit components 31 and 32 independently powered as shownand described. For intended operation in free suspension by means of a flexible manipulating line, the housing 10 of the earth drill characterized by the counter-rotating bit components. must be restrained from rotational reaction -to the variable torques of excavating action, to which end the concept of the instant invention applies automatic and continuous balancing of the torque loads occasioned through independent, counter-rotating drive of the bit components i and. thereby obviates, with manifest advantage, all need for anchoring thedrill housing to surfaceinhib'it its rotation as operative drive of either of the bit components 31 and 32 is reflected as proportional current demand at the driving motor; it is practical and feasible'within'lthe established skill ofthe pertinent variously to sense the fluctuating current demands of the separate drive-motors and variously :to apply such sensings for regulation of terminal voltage to either or both motors whereby automatically' to maintain in balance the applied torques tending, when unbalanced, to rotate the housing ofthe assembly and. thereby immobilize the housing against rotation while the bit components are simultaneously and oppositely rotated withexcavating effect. Diverse systems and techniques for automatic maintenance of torque balance between the separate and opposite drives of the earth drill of the instant invention being known and available, the diagram according to FIGURE 8, hereinafter briefly described, is merely exemplary of functionallyequivalent such systems and techniques in its disclosure of but one arrangement capable of intended and desired result which is, in specific detail and organization, itself no critical or limiting feature of the present invention apart from its broad functional capability.

Referring to FIGURE 8, and as above noted, triple leads 34 and 35 in parallel from a three-phase, alternating current supply circuit 36 connect with and reversely serve the motor stator elements 22 and 26, respectively, so that when the circuit 36 is completed for current flow through a conventional circuit breaker 37, contactors 38, and starting hook-up 39, the leads 34 land 35 are energized as protected by overload relays 40 to synchronously and oppositely drive the rotors 21 and 25 of the motors to which they connect. Without detailed elaboration of the wiring diagram, whereof the components, connections, and reactions are routine in the electrical art, it should sufiice to point out that the leads 34 and 35 serve their respective motors alike through saturable reactors 41 capable of variably regulating the voltage input to the associated motor; that said leads similarly power current transformers 42 and voltage transformers 43 effective to sense the line current and voltage in the leads; and that the signals generated at said transformers react as amplified through duplicate controller circuits utilizing magne-tic and solid state devices to regulate through the saturable reactors 41 the voltage input to the motor in a manner to maintain torque balance therebetween. Organized as illustrated, the duplicate controller circuits include at 44 provision for torque balance adjustment, at

45 provision for torque limit adjustment, and at 46 provision for individual torque adjustment, and function, as clearly appears, to accommodate compensation for variation in the electrical characteristics of the motors and at 47 for the line voltage at the installation site, to reflect torque unbalance as a current signal from the motor out of balance effective through the saturable reactors of both motors to regulate voltage input thereto for correction of the unbalance, and to limit the torque demands of the motors, even when balanced, to the rated horsepower output thereof. Variable as to detail and specific organization throughout a considerable range of functional equivalence, the system typified by FIGURE 8 is automatically effective, as hereinabove set forth, to maintain such torque balance between the separate motors of the earth drill as will effect synchronous, counterrotating, excavating drive of the bit components 31 and 32 without rotative reaction of the housing 10, irrespective of the diversities presented by operating conditions.

As an example of the operational characteristics of the earth drill and its incorporated circuit, let it be assumed that the two motor rotors Z1 and 25 are set into oppositely directed rotation at the same rotational speed. This, in turn, will cause the bits 31 and 32 to rotate in opposite rotational directions and at the same speed. The rotation of each bit imparts a torque load to the drill, but since such bits are rotating oppositely, the torque load from one bit offsets the torque load from the other and the net torque load on the drill is thus in balance. However, during drilling, the inner bit may encounter some hard material which tends to slow its rotational speed. In this instance, the outer bit will be rotating faster than the inner bit and a torque unbalance will result. When the circuit senses this unbalance, it varies the voltage supplied to the motors by means of the saturable reactor 41. This voltage variation can be applied to the outer bit motor to decrease its rotational speed until it corresponds to that of the inner bit motor, or alternatively, it can be applied to the inner bit motor to further increase its speed until the inner bit 32 is again rotating at the same speed 6 as the outer bit 31; At this time, the torque loads on the drill have again been brought into balance. If the inner bit finally bores through the hard material and its speed again increases, the circuit will again vary the voltage applied to the motors to again bring the torque loads into balance.

Organized substantially as shown and described with the manipulating line 16, flow line 29, and cables 33 interrelated in any feasible manner for conjoint extension and retraction in appropriate operative connection between the earth drill typified by the housing 10 and functionallypertient surface-based facilities, such as hoist means for the line 16, pump means for pressure supply of fluid to the flow line 29, controller circuits correlated with the leads of the cables 33, and a current supply circuit for the cable leads, the counter-rotating earth drill of the invention is a convenient, economical, and efiicient tool for the sinking of earth bores. Powered in automatically maintained torque balance as above set forth, the concentric, oppos-itely-rotating bit components exposed at the lower end of the housing 10 effectively rout and excavate earth materials to which they are applied under the weight of the lowered drill assembly and thereby efficiently extend a wall-compacted bore within and from which the drill assembly is freely reciprocable by means of the line 16. Torque-balanced in realization of the distinctive concept of the invention and hence rotationally immobilized in freely-reciprocable coaction with the bore under development, the elongated, cylindrical housing 10 serves to guide the earth drill in its production of straight bores to desired depths.

Since changes, variations, and modifications in the form, construction, and arrangement of the elements shown and described, particularly with respect to the bit components and controller circuits utilized, may be had without departing from the spirit of my invention, I wish to be understood as being limited solely .by the scope of the appended claims, rather than by any details of the illustrative showing and foregoing description.

I claim as my invention:

1. An earth drill comprising:

a hollow housing having an upper and a lower end and adapted to be suspended at its upper end to a flexible cable;

an elongated hollow sleeve having an upper end which is rotatably mounted within said housing and a lower end which projects beyond the lower end of said housing;

an elongated stem disposed within said hollow sleeve;

said stem having an upper end rotatably mounted within said housing and a lower end which projects beyond the lower end of said housing;

an inner bit member attached to the lower end of said stern;

an outer bit member attached to the lower end of said sleeve and surrounding said inner bit member;

said inner bit member projecting below said outer bit member;

a first electrically operable drive means disposed within said housing and attached to said sleeve;

a second electrically operable drive means disposed within said housing and attached to said stem;

said first and second drive means being operable to drive said sleeve and said stem in opposite directions and hence to set said inner and outer bit members into counterrotation to produce drilling of the earth;

said inner and outer bit members producing respectively a first and a second torque load due to rotation; and

control means connected to said electrically operable drive means to vary the voltage imparted to the respeotive drive means to vary the speed thereof to bring said first and second torque loads into balance during drilling to prevent any rotational movement of said housing.

, 2. AnJearth drill as, defined in claim 1. wherein said electrically operable drive. means arev electric motors.

3. An earth drill. as defined in vclaim 2 wherein each of said electric motors includes a rotor anda stator and wherein said stators are fixed to said housing while said rotors are secured to said sleeve and said stem respec-" tively. ,7 l V v 4. An earth drill as defined in claim 1 wherein said stern upper end projects above said sleeve upper end'and wherein said stern'and said sleeve areqrotatably mounted with said housing by bearing means secured to their re spective upper ends.

, 5. .An earth drill as definedin claim 1 but further char-' acterized by a flow conduit attached to said housing for supplying cooling fluid, and a plurality of flow passages 7750,840 2/04 FOX 17596 1,904,522 3/33 Pippin 175--96 2,002,387 5/35 Bannisteri 175-96 2,085,336 6/37 Sandstone 175-,104 2,643,360 6/53 'Koch .2.. 175-173 X CHARLESE. OC ONNELL, Primary Examiner. BENJAMIN BENDETT, Examiner. 

1. AN EARTH DRILL COMPRISING: A HOLLOW HOUSING HAVING AN UPPER AND A LOWER END AND ADAPTED TO BE SUSPENDED AT ITS UPPER END TO A FLEXIBLE CABLE; AN ELONGATED HOLLOW SLEEVE HAVING AB UPPER END WHICH IS ROTATABLY MOUNTED WITHIN SAID HOUSING AND A LOWER END WHICH PROJECTS BEYOND THE LOWER END OF SAID HOUSING; AN ELONGATED STEM DISPOSED WITHIN SAID HOLLOW SLEEVE; SAID STEM HAVING AN UPPER END ROTATABLY MOUNTED WITHIN SAID HOUSING AND A LOWER END WHICH PROJECTS BEYOND THE LOWER END OF SAID HOUSING; AN INNER BIT MEMBER ATTACHED TO THE LOWER END OF SAID STEM; AN OUTER BIT MEMBER ATTACHED TO THE LOWER END OF SAID SLEEVE AND SURROUNDING SAID INNER BIT MEMBER; SAID INNER BIT MEMBER PROJECTING BELOW SAID OUTER BIT MEMBER; A FIRST ELECTRICALLY OPERABLE DRIVE MEANS DISPOSED WITHIN SAID HOUSING AND ATTACHED TO SAID SLEEVE; A SECOND ELECTRICALLY OPERABLE DRIVE MEANS DISPOSED WITHIN SAID HOUSING AND ATTACHED TO SAID STEM; SAID FIRST AND SECOND DRIVE MEANS BEING OPERABLE TO DRIVE SAID SLEEVE AND STEM IN OPPOSITE DIRECTIONS AND HENCE TO SET SAID INNER AND OUTER BIT MEMBERS INTO COUNTERROTATION TO PRODUCE DRILLING OF THE EARTH; SAID INNER AND OUTER BIT MEMBERS PRODUCING RESPECTIVELY A FIRST AND A SECOND TORQUE LOAD DUE TO ROTATION; AND CONTROL MEANS CONNECTED SAID ELECTRICALLY OPERABLE DRIVE MEANS TO VARY THE VOLTAGE IMPARTED TO THE RESPECTIVE DRIVE MEANS TO VARY THE SPEED THEREOF TO BRING SAID FIRST AND SECOND TORQUE LOADS INTO BALANCE DURING DRILLING TO PREVENT ANY ROTATIONAL MOVEMENT OF SAID HOUSING. 